The bridge specification describes how physical network adapters
can be bridged to a virtual switch.

mtu*

xsd:int

The maximum transmission unit (MTU) of the virtual switch in bytes.

Since VI API 2.5

numPorts

xsd:int

The number of ports that this virtual switch is configured to use.
Changing this setting does not take effect until the next reboot. The maximum
value is 1024, although other constraints, such as memory limits, may establish
a lower effective limit.

The virtual switch policy specification. This has a lower
precedence than PortGroup. If the policy property is not set
and you are creating a virtual switch, then a default
policy property setting is used. If the policy property is not
set and you are updating a virtual switch, then the policy will
be unchanged.